Searching for a free tool to test your website’s speed? Google PageSpeed Insights is perfect! Here, we will break down what you need to check when your website has a problem with speed. 

There might be a lot of reasons your blog post is not getting the traffic you desire, despite being an amazingly written post that can help the targeted audience in more than one way. One of the most common—and often overlooked—reasons for a site’s low traffic is the speed of its web pages.

Yes, you read this correctly. If your web page loads slowly on desktop and mobile devices, it affects the SEO and user experience and, ultimately, the web page’s traffic.

Since Google takes note of slow and fast web pages, you will need a thorough plan to guide your site’s web pages to get past this test. Of course, the faster your web page’s speed is, the more it will get noticed by Google, placing it at the top of the search results, leading to more traffic. That is what every website desires nowadays!

To make things easier, tools to test the speed of web pages have been introduced, and Google themselves have come up with their own speed testing tool: Google PageSpeed Insights.

Google PageSpeed Insights

Here is your ultimate guide to understanding all the insights from Google tools like a pro.

What Is Google PageSpeed Insights?

Google PageSpeed Insights is a free analysis product by Google designed to help you optimize your website for performance on both mobile and desktop devices. It also reports on the user experience of a specific page on both kinds of devices.

After you enter the web page URL, the tool suggests how that page can be improved. The lab data that they give you is also good for debugging any issues found on the website. When it comes to Google PageSpeed Insights and its grades, it’s crucial to understand them. Since June 2021, the Google PageSpeed score has been closely related to the site’s SEO performance because of the Core Web Vitals included in the new page experience ranking factor.

Regarding the basics, Google PageSpeed Insights is one of Google’s tools to measure and improve your site’s performance on mobile and desktop devices. The first thing PageSpeed Insights provides is your page’s overall performance score. Lighthouse, an open-source tool powered by Google’s team, determines the score.

Lighthouse runs different audits, including a performance one. The performance audit assesses several metrics, and then, Lighthouse determines the performance score of the web page you’ve provided.

To get started with Google PageSpeed Insights and know your score, here is what you need to do:

  1. Go to the PageSpeed Insights website.
  2. Type in the URL of the desired web page to check its speed.
  3.  Click “Analyse” and wait until you get the results.
  4.  You will then be directed to a page with the overall score and the analysis report.

How to Read Google PageSpeed Insights Report

Google PageSpeed Insights: Speed Up Your Website

Generally, the report will show you a detailed view of your site. This includes Field Data (Core Web Vitals), Lighthouse Lab Data, Opportunities, Diagnostics, and Passed Audits.

Throughout the report, you will find that the results are shown using colour coding to make it easier for the tool’s users to understand which aspect of their site needs improvement.

  • Green = Good/Acceptable performance.
  •  Yellow = Improvement is needed.
  •  Red = Poor performance.

Field Data

Google PageSpeed Insights provides field data that lets you check what your actual users are experiencing. The field data is stored and contains all three Core Web Vitals (primary metrics), and they are:

  • Largest Contentful Paint (LCP): It refers to the loading time of the most oversized item on your page- to be fully shown. It’s responsible for 25% of your Google PageSpeed Insights score.
  • First Input Delay (FID) or Time of Interaction: It refers to how long the browser processes your user interaction with your page content
  •  Cumulative Layout Shift (CLS): It refers to how unexpected things often happen, such as issues with your content order or layout disorder. It’s responsible for 15% of your Google PSI score.
Google PageSpeed Insights

Also, you can check other notable metrics of the field data, such as First Contentful Paint (FCP) (The time between you get into the website to the first block -image or text- to be loaded fully, affecting 10% of your score), Interaction to Next Paint (INP), and Time to First Byte (TTFB).

Lighthouse Lab Data

Google PageSpeed Insights

Lighthouse is the way to go for analyzing and scanning your website based on Google’s standards on how to treat URLs. It is a distinct, open-source tool that Google supports. You can use it separately to get a broad overview of your website’s performance or check it out through the Google PageSpeed Insights dashboard. By generating an audit report, the Lighthouse feature will be your assistant to find out different aspects you don’t need to overlook to enhance your website’s authority.

Lighthouse assesses the previously mentioned Core Web Vitals and three other metrics: Speed Index (the time between when the screen is fully loaded and when you can see the visual content- it affects 10% of your score), Total Blocking Time (the time between when the first item on your page fully loaded and when the visitor can interact with it, affecting 30% of your score), and Time to Interactive.

The Google PSI score is based on “lab data.” This means that Google PageSpeed Insights, through Lighthouse, collects performance data in a controlled, simulated environment with predefined devices and network settings. This means that it doesn’t reflect the user’s experience 100%.

Audits, Opportunities, and Diagnostics

Google PageSpeed Insights

Throughout your report, GPSI offers diagnoses of any performance issue it encounters on your web page. The problems are ranked according to the following audits: PerformanceAccessibilityBest Practices, and SEO. For each section, they will give you an overall score, which issues are blocking your site, and how to fix them. PSI gives these issues the name “Opportunities.”


So, for example, let’s say one of the opportunities in the Performance audit is “properly sized images.” Once you click on that “opportunity,” it will show you which images are causing the issues and suggest how to fix them. If you scroll down past it, you will find “Diagnostics.” This section can be your little checklist to properly check where and how you can improve the web page’s performance and enhance your site’s user experience.


The other audit that the web page passes through is Accessibility. This audit ranks how accessible your site is and what they check. It also has the “Opportunities” and “Diagnostics” sections.


SEO audit is another measurement that deserves your attention and will tell you a lot about the reasons for good or bad rankings on Google. This audit ensures that your website follows basic search engine optimisation practices.

So Why Should You Check Google PageSpeed Insights?

You might wonder why it matters after reviewing how to understand the Google PageSpeed report. Here are the main reasons to check your website’s speed frequently. 

SEO: Your website rankings can be badly hurt if you don’t analyse your mobile speed and user experience. Mobile page speed has become a direct ranking factor for both Google searches and ads. Additionally, the page experience signal was rolled out as an SEO ranking factor, which includes several signs: mobile friendliness, security, safe browsing, and core web vital metrics.

Bounce rate: It refers to how much time your audience spends on your website. The high number means your website has something wrong that sends your visitors away. One of the major factors contributing to your bounce rate is slow-loading pages. Discovering the reasons behind this through Google PageSpeed will improve your website ranking, keep your audience longer, and maybe convert them into potential customers. 

Google PageSpeed Insights

Keep your customers loyal: Small business statistics found that 79% of customers tend to stop visiting and repurchasing from a slow online store. Using Google PageSpeed Insights that offer reliable scores will give you different aspects to improve your user experience. 

Uncovering your website responsiveness: when designing and developing your website, you should also have mobile design at the forefront. Google PageSpeed Insights will help you test how your website runs on mobile. Remember how many people are logging into your website through their mobile devices and how it will affect your conversion rate if it’s slower than they expect. In this instant gratification era, it’s all about speed. 

While browsing your Google PSI score, it’s split between desktop and mobile. This means that you can view how your site or web page is doing on the user’s different devices. You may not be able to get as good a mobile score as a desktop one because the internet connection on a mobile is slower than others.

Constantly updated tool: Google PSI has become more reliable since the latest changes. In November 2018, Google released PageSpeed 5.0, a new version that started using the Chrome user experience data sheet. Then, in May 2020, Lighthouse 6.0 arrived, and more metrics were added. The same ones we see now in our Google PageSpeed Insights tool capture the overall performance and user experience.

Putting you on the right track: The PageSpeed score and its metrics help you understand how your site is performing, and you should follow the PSI’s recommendations to improve your score.

Pro tip: You shouldn’t rely solely on Google PageSpeed Insights. Since the Google PageSpeed score is not 100% accurate, an improvement in the grade usually reflects an improvement in the loading time. Also, remember the Google PageSpeed score is not a ranking factor; you must take care of the core web vitals metrics. They are part of the new page experience ranking signal that affects your organic visibility.

Things to Consider When Using Google PageSpeed Insights

However, Google PageSpeed Insights analyses your website based on aggregate data pulled from your user behaviour; you must be aware of many things to capitalize on the tool’s features. 

Average Image Width on Mobile is Less Than Desktop

By default, Lighthouse simulates a 3G connection, so comparing this mobile score to the desktop one is slightly unfair. The desktop’s connection will always be faster. But it’s not the whole story. Other reasons lie behind your slow mobile version loading.

Let’s say you have a slider containing a more significant and prominent image of around 2,000 pixels. This image would be fine on a desktop, whereas the average width is 19,000 or 14,000 pixels. But on the mobile, you need to optimise it as the maximum width is 700 pixels. So the image dimensions will have a substantiated negative effect on mobile browsing speed. That’s why depending on the device, you should always correct the load to the correct size.

How can you apply this?

Serve scalable resized images on mobile.

The Size of Images Are Different on Mobile and Desktop

Then again, you can see exactly what issues there are offering for you to fix on mobile as well.

Your website loading on mobile might be slower because of the size of the image files. Always keep your image size less than 500MB. In terms of mobile speed, the lesser, the better. That’s why image optimisation will always significantly impact your mobile score more than your desktop one.

Getting a 100 Score Mobile is Nearly Impossible

That’s absolutely obvious for the reasons mentioned earlier. However, getting a 100 % score on a desktop is really accessible if you optimise it according to Google’s recommendations

It’s All About Your User Experience

Having a 100 score is always preferred. Who doesn’t like it? However, you don’t need to be only concerned about it.

For example, Google won’t penalise you if you don’t have over a 98 score.

What you want to be concerned about is your user experience, how quickly your website is loading, and how valuable your content is to your target audience. So keep fixing any issues as long as you can do that and find opportunities that will give you an advantage over your competitors. 

Use Google PageSpeed Insights to Analyse Your Competitors’ Sites

You can do this with any website as long as the website isn’t being blocked by robots or passwords. That means you can enter your competitors’ websites to find out where you’re standing and make a quick comparison to prioritise your audit strategy. 

Other Tools You Can Use For Speed Audit

Google PageSpeed Insights is reliable, but other tools are available if you want to look up the performance and speed of a website. Here you can find other free tools to analyse your page speed:


Additional performance and speed test tools are out there, such as GTmetrix, a free performance tool you can use to see how well your site is performing.

The difference between Google SPI and GTmetrix is the location used for the performance test. Other than that, they both use the Lighthouse performance metrics, so the score should be the same if you scan your website through both, but you might still see a discrepancy between the two scores.

How does it work?

Just go to GTmetrix and type in the website link you want or the web page that you want to test. Wait a couple of minutes, and the tool will analyse your site and URL and then give you a score and opportunities to fix.

Google PageSpeed Insights

It’ll give you a summary of your overall performance metrics. The report will include many benchmarks like Google SPI, such as First Contentful Paint, Time to Interactive, Total Blocking Time, and more.

You can also click on Waterfall, which will give you a detailed chart showing your web page’s request-by-request visualisation and loading behaviour—it’s one of the most useful features for troubleshooting and debugging any performance issues that you might have.

As mentioned, GTmetrix and Google PageSpeed use the Lighthouse performance metrics, so the scores should be the same. 

Pro tip: always choose the nearest location server when testing your website through GTmetrix, as you can see how your performance can change according to the server location.


Another tool that you can use to measure performance is Pingdom. Still, it isn’t easy to compare Google PSI and GTmetrix to Pingdom as the latter doesn’t use Lighthouse. So, Pingdom won’t give you any information on core web vitals. It just provides a grade based on your loading time. 

Also, it is not free. You have to sign up and enjoy a 30-day free trial, but after that, you will be charged at least $10 based on your plan. 

Google PageSpeed Insight has evolved quickly. It’s very important to help you understand exactly what your performance score is like and your user’s experience of your website’s performance.

How Can Profiletree Help You?

Do you want to foster beautiful growth throughout your organisation?

You’re invited to analyse your website with the help of our developers and SEO experts, who will work as an extension to your team.

You don’t need to worry about your website speed, traffic, design, or why you struggle to generate conversions.

We will help you join the dots between your business objectives, market needs and creative ideas to set your company up for sustainable success. 

Uncover what it takes to make your brand stand out and how businesses shine in this intense competition.

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